Messages in this thread Patch in this message | | | From | Josh Poimboeuf <> | Subject | [PATCH RFC 02/10] perf: Remove get_perf_callchain() 'crosstask' argument | Date | Wed, 8 Nov 2023 16:41:07 -0800 |
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get_perf_callchain() doesn't support cross-task unwinding, so it doesn't make much sense to have 'crosstask' as an argument. Instead, have perf_callchain() adjust 'user' accordingly.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> --- include/linux/perf_event.h | 2 +- kernel/bpf/stackmap.c | 5 ++--- kernel/events/callchain.c | 6 +----- kernel/events/core.c | 8 ++++---- 4 files changed, 8 insertions(+), 13 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index f4b05954076c..2d8fa253b9df 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1534,7 +1534,7 @@ extern void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct p extern void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs); extern struct perf_callchain_entry * get_perf_callchain(struct pt_regs *regs, bool kernel, bool user, - u32 max_stack, bool crosstask, bool add_mark); + u32 max_stack, bool add_mark); extern int get_callchain_buffers(int max_stack); extern void put_callchain_buffers(void); extern struct perf_callchain_entry *get_callchain_entry(int *rctx); diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index b0b0fbff7c18..e4827ca5378d 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -294,8 +294,7 @@ BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map, if (max_depth > sysctl_perf_event_max_stack) max_depth = sysctl_perf_event_max_stack; - trace = get_perf_callchain(regs, kernel, user, max_depth, - false, false); + trace = get_perf_callchain(regs, kernel, user, max_depth, false); if (unlikely(!trace)) /* couldn't fetch the stack trace */ @@ -421,7 +420,7 @@ static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, trace = get_callchain_entry_for_task(task, max_depth); else trace = get_perf_callchain(regs, kernel, user, max_depth, - false, false); + false); if (unlikely(!trace)) goto err_fault; diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index 1e135195250c..aa5f9d11c28d 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -178,7 +178,7 @@ put_callchain_entry(int rctx) struct perf_callchain_entry * get_perf_callchain(struct pt_regs *regs, bool kernel, bool user, - u32 max_stack, bool crosstask, bool add_mark) + u32 max_stack, bool add_mark) { struct perf_callchain_entry *entry; struct perf_callchain_entry_ctx ctx; @@ -209,9 +209,6 @@ get_perf_callchain(struct pt_regs *regs, bool kernel, bool user, } if (regs) { - if (crosstask) - goto exit_put; - if (add_mark) perf_callchain_store_context(&ctx, PERF_CONTEXT_USER); @@ -219,7 +216,6 @@ get_perf_callchain(struct pt_regs *regs, bool kernel, bool user, } } -exit_put: put_callchain_entry(rctx); return entry; diff --git a/kernel/events/core.c b/kernel/events/core.c index b0d62df7df4e..5e41a3b70bcd 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7592,16 +7592,16 @@ perf_callchain(struct perf_event *event, struct pt_regs *regs) { bool kernel = !event->attr.exclude_callchain_kernel; bool user = !event->attr.exclude_callchain_user; - /* Disallow cross-task user callchains. */ - bool crosstask = event->ctx->task && event->ctx->task != current; const u32 max_stack = event->attr.sample_max_stack; struct perf_callchain_entry *callchain; + /* Disallow cross-task user callchains. */ + user &= !event->ctx->task || event->ctx->task == current; + if (!kernel && !user) return &__empty_callchain; - callchain = get_perf_callchain(regs, kernel, user, - max_stack, crosstask, true); + callchain = get_perf_callchain(regs, kernel, user, max_stack, true); return callchain ?: &__empty_callchain; } -- 2.41.0
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